Alcohol
Be very careful drinking alcohol while taking diazepam.
You can drink a small amount of alcohol while taking diazepam but having the two together is likely to make you very sleepy. This will be most noticeable during the early part of your treatment.
Taking large amounts of alcohol and diazepam together could affect your breathing, especially if you have an existing lung problem.
If you need to drive a car or ride a bike, or use machines at work, taking alcohol and diazepam together could be dangerous to yourself and other people.
Street drugs
Diazepam does not mix well with street drugs.
It is very easy, and serious, to overdose with any combination of diazepam and drugs.
Using cannabis with diazepam will make its sedative effect worse. You could go into a very deep sleep where you do not breathe properly and have difficulty waking up.
Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis. For more information, have a look at our drugs and alcohol page.
Using heroin or methadone with diazepam will also increase their combined sedative effects. You could go into a very deep sleep where you do not breathe properly and have difficulty waking up.
Using cocaine or other stimulants (like ecstasy, amfetamines, MDA, 6-APB etc.) with diazepam is likely to lead to a reduced stimulant effect. This could lead you to increase the dose of the stimulant to make up for it, which could be very dangerous.
Smoking
If you start or stop smoking while you are taking diazepam, you may have to change your dose. This is because cigarette smoke affects the amount of diazepam in your body.
If you already smoke when you begin taking this medication, you will probably need a higher dose than somebody who does not smoke. You should tell your doctor if you smoke and how much, so that they can prescribe the correct dose for you.
If you stop smoking, the level of diazepam in the body could rise, and you might need to reduce your dose of diazepam slowly over one week.
If you (re)start smoking, you might need to increase it again.
Go to your doctor for advice if you stop or start smoking.